Is there an existing library method that checks if a String is all upper case or lower case in Java?

I know there are plenty of

upper()

methods in Java and other frameworks like Apache commons lang, which convert a String to all upper case.

Are there any common libraries that provide a method like

isUpper(String s)

and

isLower(String s)

, to check if all the characters in the String are upper or lower case?

EDIT:

Many good answers about converting to Upper and comparing to this. I guess I should have been a bit more specific, and said that I already had thought of that, but I was hoping to be able to use an existing method for this.

What I needed this method for, was to capitalize names of hotels that sometimes came in all uppercase. I only wanted to capitalize them if they were all lower or upper case.
I did run in to the problems with non letter chars mentioned in some of the posts, and ended up doing something like this: